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In this design, the user has a different screen for each decision. For instance, the The user also must take one picture of each object individually. Then when all of the pictures have been taken, the user decides which object to review. This choice seems to be irrelevant, because the user should not have spent time taking pictures of object he/she does not want to review. Efficiency can be improved by aggregating the 'snap picture' and 'choose objects to review' subtasks into less screens. For instance, one picture could be taken and the very next screen shows the shopping cart with information about each object specified.
For the purposes of this application, the user must spend time annotating the picture to specify which object to review. The method of annotation in this design is very quick and efficient.
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The method of comparing objects is somewhat efficient; if the user wants to compare a specific detail about two objects the user must travel back and forth between detail screens. The user does not have the ability to move that detail to the shopping cart screen where all objects and main details (such as stars) can be viewed.
Learnability
Given this application starts by going right to the camera, the user will not know exactly what to do at first. Only after taking a random picture and going through the process will the user figure out how the application works. This detracts from the initial efficiency of learning the application, because there are no blatant instructions for the user to read. In the long run, the user does not have to bypass a start screen or instruction screen that tells the user what it already knows. The application efficiently starts right out with a camera. After taking a picture, the user can touch randomly to learn exactly how to specify which object they are interested in. After specifying, the application reinforces exactly how to take pictures of object and annotate by allowing the simple process to be repeated. This also gives the user practice. Selecting which objects to review is fairly easy to learn. The pictures selected will highlight in some way to show the user exactly what is selected.
Design B
This time, Sally can collect information about all the products she’s interested in more quickly by taking pictures that each have multiple bicycles in them:
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